In cable trays of the type defined above, the free ends of the parallel arms of the U-shaped transverse wires are generally trimmed in a plane transverse their general axes so that they have circular sharp edges. Owing to the presence of these sharp edges, the insulating covering of the electrical cables to be disposed in the tray may be damaged during their insertion in the tray and the operators handling the cables of the tray may be injured.
Various measures have been proposed for solving the above-mentioned problems and consist, in summary, in rounding off the free ends of the parallel arms of the U-shaped transverse wires, in butt-welding the longitudinal edge wires to the free ends of the arms of the U-shaped transverse wires, or in bending these ends.
However, these measures have been found disadvantageous because they require additional operations which necessarily have to be performed during the production of the various sections of the tray and which thus render their fabrication too expensive. Moreover, in some cases, these measures lead to a change in the structure of the tray which renders it less suitable for being bent to produce curved tray sections.